1. Field of the Invention
The present invention relates to a geared motor for a self-traveling carrier wherein a motor for driving a wheel of the self-traveling carrier adapted to travel through the rolling of the wheel on a track, and a gear box housing therein a speed change mechanism disposed between a motor shaft of the motor and the wheel, are rendered integral with each other.
2. Description of the Prior Art
In Japanese Utility Model Laid Open No. 55166/89 there is disclosed a self-traveling carrier of a conveyor for use in a physical distribution system. This self-traveling carrier, as shown in FIG. 7, is provided with a driving trolley 11 and a driven trolley 12 both capable of moving along a traveling rail (track) 2 and disposed of intervals from each other in the longitudinal direction, a connecting member 13 for connecting both trolleys 11 and 12, and a goods table 15 mounted to the connecting member 13 through a pair of front and rear hangers 14.
As shown in FIG. 8, the driving trolley 11 is provided with a driving roller (wheel) 16 adapted to roll on an upper surface of an upper flange of the traveling rail 2, four guide rollers 17 disposed on both sides of the upper flange of the rail 2 and of a lower flange of the rail, an electric motor 18 for rotating the driving roller 16, a reduction mechanism 19 with a clutch device disposed between the driving roller 16 and the electric motor 18, and a gear box 50 which houses therein the reduction mechanism 19 with a clutch device.
According to the construction of the reduction mechanism 19, power is transmitted to an output shaft 23 through a pinion 30 mounted on a motor shaft 29, a gear 34 meshing with the pinion 30, a bevel pinion 35 formed integrally with an intermediate shaft 33 onto which is fixed the gear 34, and further through a bevel gear 28 meshing with the bevel pinion 35.
Though not shown, there is also provided a current collector adapted to slide on a current collector rail 3.
Upon rotation of the motor 18, the driving roller 16 rotates through the reduction mechanism 19 with a clutch device, so that the driving trolley 11 travels on the traveling rail 12. Consequently, the driven trolley 12 connected to the driving trolley through the connecting member 13 also travels on the rail 2, whereby the goods table 15 mounted to the connecting member 13 through the hangers 14 can be moved.
Further, even in the event of occurrence of trouble or the like, the self-traveling carrier can be easily moved manually because the mechanical connection between the motor shaft 29 and the driving roller 16 can be released by the function of the clutch device.
In such a conventional self-traveling carrier, however, there have been the following problems associated with its geared motor portion (the portion including both the motor and the gear box).
a: Since there is adopted a structure wherein the motor 18 is suspended vertically on the side of output shaft 23 projecting in the direction opposite to the driving roller 16 with respect to a bearing portion (indicated at numerals 21 and 22 in FIG. 8) which bears the wheel load, a projected area of the geared motor in the advancing direction of the carrier 1 corresponds to an "axial sectional area" of the geared motor and thus it is very large.
More particularly, from the nature of the carrier which travels on the track, it is necessary that an "obstacle-free space" larger than the projected area in the advancing direction of the carrier is ensured around the track and throughout the whole section of the track. Therefore, if the projected area in the carrier advancing direction of the geared motor is large, the mounting of the self-traveling carrier itself may be impossible, or it will be impossible to utilize the space around the track effectively for other purposes.
b: The reduction mechanism portion comprises such conventional combinations as the pinion 30--gear 34 and the bevel pinion 35--bevel gear 28, also, the projection of the clutch device portion is fairly large, so the reduction in size of the gear box into a compact size is not attained, and the projected area itself of the gear box is also large.
c: The mounting of the geared motor to the carrier is exclusively for the self-traveling carrier, so with one type of a gear box, it is impossible to cope with various mounting methods.
This point will now be explained more concretely. In a physical distribution system or the like comprising a plurality of self-traveling carriers for example, it is efficient to operate of the system a necessary portion only when required. In driving the self-traveling carriers, it is more convenient for each self-traveling carrier to be independent. Also, it is often necessary to change the position of each self-traveling carrier for changing a conveyance path. Also, in such cases, it is more convenient for each self-traveling carrier to be independent.
For this reason, as in the above conventional example, a self-traveling carrier with a "motor," more exactly a self-traveling carrier with a "geared motor" comprising a motor and a speed change mechanism (generally a reduction mechanism), has become popular. Therefore, in this case, when viewed from the entire self-traveling carrier, the "geared motor" merely constitutes a portion of the carrier. Also as to each self-traveling carrier, it merely constitutes a portion of the physical distribution system when viewed from the whole of the system.
In relation to the entire physical distribution system, therefore, various members which are obstacles to the mounting of the geared motor are often present around the self-traveling carriers. Further, with respect to a self-traveling carrier which is already in use, in the case where a certain member is newly present within a projected area in the advancing direction of that carrier, it sometimes becomes impossible for the geared motor portion of the carrier to remain mounted as it is.
In such a case, the foregoing prior art permits only "one face" to effect mounting of the geared motor portion of the self-traveling carrier and hence it is impossible to effect various modes of mounting correspondingly to the positions of other devices and members.
Generally, in such a case, it is necessary to beforehand provide various geared motors different in the mounting face and mounting method and to select a suitable geared motor according to conditions. As the entire physical distribution system, however, it is not desirable to provide a variety of geared motors, from the standpoint of maintenance and control of the system.